WASHINGTON — NASA said Jan. 4 it is delaying a planned visit to the United States by Dmitry Rogozin, the head of the Russian space agency Roscosmos, a trip that had become increasingly controversial.

In response to a SpaceNews inquiry, NASA Press Secretary Megan Powers said Rogozin’s visit to the United States, which had been scheduled for February, has been postponed indefinitely.

“NASA has informed the Russian space agency, Roscosmos, that the proposed visit of Roscosmos Director General, Dr. Dmitry Rogozin, currently planned for February 2019 will need to be postponed. A new date for the visit has not been identified,” Powers said. She gave no explanation for the delay.

The planned visit, first discussed in October when NASA Administrator Jim Bridenstine visited Russia and met with Rogozin, had gained increasing scrutiny in recent days after Politico reported Jan. 1 criticism of the planned visit, which reportedly would include stops at the Johnson Space Center and Rice University in Houston. Rogozin, who previously was deputy prime minister of Russia, is one of several Russian officials sanctioned by the U.S. government for their role supporting the annexation of Crimea in 2014, barring their entry into the United States.

Among the critics cited in that report was Sen. Mark Warner (D-Va.), vice chairman of the Senate Select Committee on Intelligence. “It absolutely sends the wrong message to lift sanctions, even temporarily, for the purpose of inviting him to speak to students at one of our nation’s premier universities,” he said.

Since that report other senators have spoken out about the planned visit. “America’s message to the Kremlin should be unequivocal: actions have consequences,” said Sen. Jeanne Shaheen (D-N.H.), ranking member of the Senate appropriations subcommittee that funds NASA, in a Jan. 2 statement. “Administrator Bridenstine’s invitation to Dmitry Rogozin, one of the leading architects of the Kremlin’s campaign of aggression towards its neighbors, undercuts our message and undermines the United States’ core national security objectives.”

Shaheen called on Bridenstine to withdraw the invitation, as did Sen. Bob Menendez (D-N.J.) a day later. “I strongly urge you to immediately withdraw this invitation given the Trump Administration’s current sanctions on this individual,” Menendez said in a Jan. 3 letter to Bridenstine released by his office. He added that if NASA went ahead with the visit, he would introduce a “resolution of disapproval,” a provision of a law passed in 2017 called the Countering America’s Adversaries Through Sanctions Act that provides congressional oversight over changes to sanctions against Russia.

An agency source, speaking on background, said that NASA received approval for meetings with Rogozin from the Treasury Department, which oversees sanctions, in June. The substance of those meetings would be limited to civil space cooperation between the United States and Russia.

During his earlier tenure as deputy prime minister, Rogozin threatened to cut off access to the International Space Station by American astronauts, who then, as now, rely on Russian Soyuz spacecraft to get to and from the ISS. That included an infamous tweet that suggested NASA would need a trampoline to get to the station. Despite the threats, there were no interruptions in U.S. access to the station.

Bridenstine, in a September interview, said his relationship with Rogozin was good, although at the time the two had not yet met in person and had talked in just a single phone call. He dismissed Rogozin’s earlier rhetoric as part of politics, noting that, as a member of Congress, he also had made “aggressive” comments about Russia.

“We’ve been able to make sure that space has been set apart from all of these sometimes terrestrial challenges that we have with our international partners, especially in this case, Russia,” Bridenstine said then. “It’s my intent to keep that relationship strong. It’s his intent as well.”